GetValue for Windows - Graph Digitizer Equipped with Electrochemical Analyzer

Hidenobu SHIROISHI, Yuuki KABURAGI, Michiko SEO, Sumio TOKITA and Masao KANEKO

1 Introduction

2 Implementation

3 Usage

Figure 1. Screen shots of "GetValue"

1. Loading the image file
   First, a chart image is inputted into to a computer with a scanner by using another program that a user usually employs for inputting the image. The image must be saved as "bmp" or "jpg" format. After "GetValue" is started, the image file is loaded by choosing [File] ® [Open] menu. The image can also be brought to this program from clipboard using [Edit] ® [Paste picture] menu.
   
2. Adjustment of an inclined image
   The "Image rotation button" (Figure 1(e)) enables the adjustment of the angle of the image. Two data points must be specified from the left side on the line that you make horizontal. These points can be moved by dragging. After specifying two data points, click the "execute" button to rotate the image. A progress bar shows how much the process passed.
   
3. Setting of a reference frame
   Next, setting of a reference frame is needed for the measurement. Either of the two methods shown below could be selected.
   (a) Specification of two points on the image
   After selecting the "Specification of two data point button" (Figure 1(c)), click on the image to specify two data points in the order: upper left and lower right. After clicking, these points can be moved by dragging. Input coordinates after the coordinate transformation. The user can save the parameters by clicking on the "Save settings" button.
   (b) Specification of the dpi of a chart image and a datum point on the image
   After clicking on the "Specification of a datum point and dpi button" (Figure 1(d)), click on the image to specify a datum point. The program allows you to drag the point. Input the parameters for the coordinate transformation: dpi of the image, coordinates of a datum point after the transformation, and values per 1 cm after the transformation.
   
4. Acquisition of values on the image
   There are two modes to obtain values on the image. A selected series of points is available for the edit.
   (a) Specific point mode
   After selecting the "Point-setting button" (Figure 1(f)), choose a series from an image combo box (Figure 1(h)). Put a point on which you want to obtain a value. The points can be moved by dragging, and erased by clicking on the right button.
   (b) Spline mode
   After clicking on the "Spline mode button" (Figure 1(g)), operate this mode like (a). More than four points are needed for calculating the spline curve because of the cubic spline function. The same x value cannot be specified in this mode. For example, when obtaining values on a cyclic voltammogram, another series should be selected at the reverse scan.
   
5. Display of the numerical values
   By clicking on the button for displaying the numerical values (Figure 1(I)), a table is obtained. The data are transferred to the clipboard by selecting a copy menu.
   
6. Analyses of data
   (a) Linear least-square method
   The data can be analyzed by least-square method by [Analysis] ® [Least Square] menu.
   (b) Estimation of diffusion coefficient
   Figure 2 shows the window of Cottrell's equation analysis. The analysis can be used by [Analysis] ® [Cottrell's equation] menu. The user must input the parameters : y scale, concentration, and the number of electrons ( n ). The diffusion coefficients are calculated by [Calculation] button.
   (c) Battery analysis
   Figure 3 shows the window of battery analysis. The user can obtain parameters such as open-circuit voltage, short-circuit current, and fill factor.
   

Figure 2. Estimation of Diffusion coefficients using Cottrell's equation.

Figure 3. Illustration of battery analysis.

4 Agreements for using the program

The authors acknowledge a Grant-in-Aid for JAERI's Nuclear Research Promotion Program (JANP) from Japan Atomic Energy Research Institute.

References